N-glycidyl compound

ABSTRACT

The new compound N,N,N&#39;N&#39;-tetraglycidyl-3,3&#39;-diethyl-4,4&#39;-diaminodiphenylmethane and curable resin compositions containing it.

The present invention relates to N-glycidyl compound.

Epoxide resins are widely used in industry as adhesives, coatings,castings, insulants and in reinforced composites. A variety ofchemically distinct epoxide resins are available for this purpose. Suchresins are commonly glycidyl ethers or esters derived fromepichlorohydrin and a bisphenol or a dicarboxylic acid. Where goodperformance at high temperature is required, however, as is the case inthe aerospace industry, the use of epoxide resins having glycidyl groupsattached to aromatic amino groups is often preferred. Such materials areprepared by reaction of the aromatic amine with about 0.8-10equivalents, per amino hydrogen atom, of epichlorohydrin; followed byconventional dehydrochlorination, using an alkali. This reaction may becarried out in the presence of an acid catalyst in the manner described,e.g. in British Patent Specification No. 2111977.

In European Patent Specification 143075 a process for the production ofimproved N-glycidyl amines having a higher epoxide content and a lowerviscosity than previously-known materials, is described. The improvedN-glycidyl amines of EP 143075 are produced by effecting the reaction ofaromatic amines with at least 0.7 equivalent, preferably 0.8 to 1.5equivalents, per amino equivalent of the aromatic amine ofepichlorohydrin in the presence of a di- or higher-valent metal salt ofa) nitric acid or perchloric acid or b) a carboxylic or sulphonic acidsubstituted by fluorine, chlorine or bromine on the carbon atom alpha tothe carboxylic or sulphonic acid group.

We have now found that by reacting a specific aromatic amine, namely,3,3'-diethyl-4,4'-diaminodiphenylmethane, with epichlorohydrin, a newN-glycidyl amine is produced, viz.N,N,N'N'-tetraglycidyl-3,3'-diethyl-4,4'-diaminodiphenyl methane havingimproved properties, especially improved viscosity properties relativeto the generality of N-glycidyl amines produced by the process of the EP143075.

Accordingly, the present invention provides the compoundN,N,N'N'-tetraglycidyl-3,3'-diethyl-4,4'-diaminodiphenyl methane, havingthe formula (I): ##STR1##

While generic structures, embracing broadly the compound of formula (I)and even describing reaction mixtures containing some proportion of thecompound of formula I have been disclosed, e.g. in EP 143075 and inJP-074552, the pure specific compound of formula I is believed to benovel.

The compound of formula I may be produced, as indicated hereinbefore, byreacting 3,3'-diethyl-4,4'-diaminodiphenyl methane with epichlorohydrin,preferably in the presence of a catalyst and, most preferably, using thecatalysts described in EP 143075.

Thus, specific preferred salts for use as catalysts in the production ofthe compound of formula I are magnesium perchlorate, calciumperchlorate, zinc perchlorate, nickel perchlorate, magnesium nitrate,manganese nitrate, lanthanum nitrate, ytterbium nitrate, uranyl nitrate,magnesium trifluoroacetate, manganese trifluoroacetate, nickeltrifluoroacetate, vanadyl trifluoroacetate, magnesiumtrifluoromethanesulphonate, colbalt trifluoromethanesulphonate,lanthanum trifluoroacetate, lanthanum trifluoromethane sulphonate,magnesium trichloroacetate, magnesium-2,2-dichloropropionate andmagnesium tribromoacetate.

The amount of salt present in the reaction between3,3'-diethyl-4,4'-diaminodiphenyl methane and epichlorohydrin isgenerally within the range of from 0.1 to 10 parts, especially 0.4 to 2parts, per 100 parts of 3,3'-diethyl-4,4'-diaminodiphenyl methane.

The preferred mode of incorporating the catalyst into the reactionmixture comprising 3,3'-diethyl-4,4'-diaminodiphenyl methane andepichlorohydrin, is by adding the catalyst dissolved in an inertsolvent. Examples of inert solvents include 2-methoxyethanol,isodecanol, ethyleneglycol, diethyleneglycol, N-methylpyrrolidone, gammabutyrolactone, benzyl alcohol, dibutyl phthalate, butane-1,4-diol, ethylmethyl ketone, benzene and toluene.

The reaction is usually effected at an elevated temperature, preferablyat a temperature within the range of from 50° C. to 100° C. When thereaction between 3,3'-diethyl-4,4'-diaminodiphenyl methane andepichlorohydrin is complete, usually within 1 to 12 hours, thedehydrochlorination is effected in conventional manner, e.g. by addingsodium hydroxide or potassium hydroxide, optionally with the addition,as phase transfer catalyst, of a quaternary ammonium halide such asbenzyltrimethyl ammonium chloride. After heating, e.g. for 2 to 10 hoursat 50°-100° C., the reaction mixture may be washed with water, and theorganic phase separated to produce the desired N-glycidyl amine offormula I. The compound of formula I may be purified by conventionalmethods, if desired, prior to use e.g. in curable epoxy resincompositions.

The present invention also provides a curable resin compositioncomprising

a) the compound of formula I, as epoxide resin component;

b) a hardener; and, optionally,

c) a curing accelerator.

The hardener component b) is preferably a nitrogen-containing compoundwhich remains inert towards the epoxy compound of formula I below acertain "threshold" temperature, which is usually at least 80° C. and ispreferably at least 100° C., but which reacts rapidly to effect curingonce that threshold temperature has been exceeded. Such materials arewell known in this art and are commercially available. They includeboron trichloride/amine and boron trifluoride/amine complexes;dicyandiamide; melamine; diallylmelamine; guanamines such asacetoguanamine and benzoguanamine; aminotriazoles such as3-amino-1,2,4-triazole; hydrazides such as adipic-, stearic- andisophthalic hydrazides; semicarbazide; cyanoacetamide; and aromaticpolyamines such as diaminodiphenyl sulphones. The hardener component b)may also be acidic in nature, examples of which are polyphenols,polycarboxylic acids and, especially di- and polycarboxylic acidanhydrides, most particularly hexhydrophthalic anhydride or methyltetrahydrophthalic anhydride.

The curable resin composition according to the present inventiongenerally contains 1 to 60 wt. %, preferably 5 to 50 wt. % of thehardener component b), based on the amount of epoxide resin componenta).

The optional curing accelerator, component c) of the compositions of thepresent invention, are again known materials in this art and theselection of the accelerator will depend on the type and reactivity ofthe hardener component b). Examples of such accelerators include solidsolutions of a nitrogen base having a boiling point above 130° C. and aphenolic polymer which is an addition polymer of a phenol bearing anunsaturated substituent, as described in European Patent Specification0200678; and a reaction product of a nitrogen base and ahalogen-substituted monomeric phenol, as described in European PatentSpecification No. 0240459. Further examples of curing acceleratorsincude; latent Lewis acid complexes such as the BF₃ -ethylamine; latentbases such as N,N-dimethylureas and BCl₃ -amine complexes; and basicaccelerators such as tertiary amines.

The amount of the optional accelerator, component c), is not criticaland may range from 0 to 15, preferably from 0 to 10 wt. %, based on theweight of component a).

The new compositions according to the present invention may also containone or more of suitable plasticizers such as dibutyl phthalate ordioctyl phthalate; inert diluents e.g. tars and bitumen; and so-calledreactive diluents, especially monoepoxides e.g. n-butyl glycidyl ether,iso-octyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether,glycidyl esters of mixed tertiary, aliphatic monocarboxylic acids,glycidyl acrylate and glycidyl methacrylate. The compositions of theinvention may also contain other polyglycidyl resins such as glycidylderivatives of polyphenols, polyalcohols, and polycarboxylic acids. Thecompositions may also contain additives such as fillers; reinforcingmaterials; polymeric toughening agents such as polyether sulphones,phenoxy resins and butadiene-acrylonitrile rubbers; colouring matter;flow control agents; flame retardants; and mould lubricants.

Suitable extenders, fillers and reinforcing materials are, e.g., glassfibres, carbon fibres, fibres of aromatic polyamides, ballotini, mica,quartz flour, calcium carbonate, cellulose, kaolin, wollastonite,colloidal silica having a large specific surface area, powderedpoly(vinyl chloride) and powdered polyolefin hydrocarbons such aspolyethylene and polypropylene.

The compositions of the present invention are useful as laminatingresins, impregnating and casting resins, powder coatings, mouldingcompositions, putties and sealing compounds, potting and insulatingcompounds for the electrical industry, but especially as casting resins,laminating resins, and impregnating resins.

The compositions of the invention are conveniently cured by heating themat a temperature in the range of from 100° C. to 200° C., especially150° C. to 180° C. Usually, heating for 60 to 180 minutes suffices toachieve curing but post-curing at higher temperatures may be necessaryto achieve optimum properties.

Relative to conventional resins, the new compound of formula I shows asubstantial reduction in viscosity, with subsequent improved ease ofprocessing, and substantial improvement in shelf life with4,4'-diaminodiphenyl sulphone, with no significant reduction in Tg.

The following Examples further illustrate the present invention.

EXAMPLE 1

3,3'-Diethyl-4,4'-diaminodiphenylmethane (100 g.), toluene (150 g.) and50% lanthanum nitrate in 2-methoxyethanol (2 g.) are stirred and heatedto 60° C. under a vacuum of 120 mm. Epichlorohydrin (158.6 g.) is thenadded, in portions, over 1 hour, the temperature being maintained at 60°C. by means of vacuum reflux. At the end of this addition, the reactionmixture is maintained at 60° C. for 15 mins. and then vacuum is broken.A further portion of catalyst solution (2 g.) is added and thetemperature raised to 80° C. and held at 80° C. for 9 hours. Thetemperature is reduced to 60° C., and 50% aqueousbenzyltrimethylammonium chloride (1.5 g.) added and the apparatus set upfor vacuum azeotrope. 50% aqueous sodium hydroxide (151 g.) is thenadded over 3 hours, water being azeotroped out under vacuum (100 mm). Atthe end of the addition, azeotrope is continued for a further 90minutes. Water (300 ml.) is then added with vigorous stirring. Theaqueous layer is discarded and the organic layer washed with 10% aqueoussodium dihydrogen phosphate (200 ml.), and evaporated in vacuo on arotary evaporator. The residue is redissolved in toluene (250 ml.),filtered and evaporated in vacuo to give a product having an epoxidecontent of 7.89 mol./kg. (94.9% of the theoretical value), a viscosityat 25° C. of 7.1 Pas, and a monomer content (measured by HPLC) of 92.9%.

EXAMPLE 2

A sample of resin from Example 1 (10 g.), 4,4'-diaminodiphenylsulphone(4.9 g.) and Aerosil R 805 (0.3 g.) are milled together in a triple rollmill. A sample of this mix is then stored at 60° C. and periodicallytested to check whether the mixture is of a sufficiently low viscosityto be still usable. After 73 days the viscosity of the mix has exceededusable limits. Another sample of the mix is cured for 3 hours at 175° C.followed by a post-cure of 2 hours at 205° C. The cured sample is foundto have a T_(g) of 261° C.

A similar composition containing the glycidyl derivative of4,4'-diaminodiphenylmethane, which itself has a viscosity at 25° C. of100.7 Pas, has a shelf life of 10 days at 60° C. and a Tg of 260° C.

We claim:
 1. A curable resin composition comprising:a) an epoxide resincomponent consisting essentially of the pure specific compoundN,N,N',N'-tetraglycidyl-3,3'-diethyl-4,4'-diaminophenylmethane; b) ahardener; and optionally, c) a curing accelerator.
 2. A compositionaccording to claim 1, in which component b) is a nitrogen-containingcompound which remains inert towardsN,N,N',N'-tetraglycidyl-3,3'-diethyl-4,4'-diaminodiphenylmethane below atemperature of at least 80° C.
 3. A composition according to claim 2 inwhich component b) remains inert towardsN,N,N',N'-tetraglycidyl-3,3'-diethyl-4,4'-diaminodiphenylmethane below atemperature of at least 100° C.
 4. A composition according to claim 1 inwhich component b) is a boron trichloride/amine or borontrifluoride/amine complex; dicyandiamide; melamine; diallymelamine; aguanamine; an aminotriazole; a hydrazide; semicarbazide; cyanoacetamide;or an aromatic polyamine.
 5. A composition according to claim 4 in whichthe guanamine is acetoguanamine or benzoguanamine; the aminotriazole is3-amino-1,2,4-triazole; the hydrazide is adipic-, stearic- orisophthalic hydrazide; and the aromatic polyamine isdiaminodiphenylsulphone.
 6. A composition according to claim 1 in whichcomponent b) is a polycarboxylic acid or a polycarboxylic acidanhydride.
 7. A composition according to claim 6 in which thepolycarboxylic acid anhydride is hexahydrophthalic anhydride or methyltetrahydrophthalic anhydride.
 8. A composition according to claim 1 inwhich the curable resin composition contains 1 to 60 wt. %, of hardenercomponent b) based on the amount of component a).
 9. A compositionaccording to claim 8 in which the curable resin composition contains 5to 50 wt. % of hardener component b), based on the amount of componenta).
 10. A composition according to claim 1 in which the curable resincomposition contains 0 to 15 wt. % of component c), based on the weightof component a).
 11. A composition according to claim 10 in which thecurable resin composition contains 0 to 10 wt. % of component c), basedon the weight of component a).
 12. A composition according to claim 1 inwhich one or more of plasticizer, an inert diluent or a reactive diluentare also present.
 13. A composition according to claim 1 in which one ormore of a filler, a reinforcing material, a polymeric toughening agent,a colouring agent, a flow-control agent, a flame retardant or a mouldlubricant is also present.
 14. A laminating-, impregnating- or castingresin, a powder coating, a moulding composition, a putty or sealingcompound, or a potting or electrically insulating compound comprisingthe composition of claim
 1. 15. A composition according to claim 1, inwhich the curing accelerator is present and is a latent Lewis acidcomplex, a base or a latent base.
 16. A composition according to claim15, in which the curing accelerator is a BF₃ -amine complex; asubstituted urea; or a tertiary amine or a complex thereof with BCl₃.17. A composition according to claim 16, in which the BF₃ -amine complexis a BF₃ -ethylamine complex and the substituted urea is monuron orchlortoluron.
 18. A composition according to claim 15, in which thecuring accelerator is a solid solution of a nitrogen base having aboiling point above 130° C. and a phenolic polymer which is an additionpolymer of a phenol bearing an unsaturated substituent; or a reactionproduct of a nitrogen base and a halogen-substituted monomeric phenol.